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2.1 1. The atmosphere is a mixture of gases that

surrounds the Earth.

2. The oxygen in the air only makes up

about 21% of the atmosphere.

The nitrogen in the air only makes up about

78% of the atmosphere.

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The atmosphere contains small particles like:Dust

Volcanic ash

Sea salt

Dirt

Smoke

3. Most of the water in the atmosphere exists

as invisible gas called water vapor.

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When the atmospheric conditions change, the

water vapor can turn into a solid.

4. The solid form of water vapor can be:Liquid -- rain

Solid – sleet, hail, or snow

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5. The atmosphere is held around the Earth

by gravity.

6. Air pressure is the measure of the force

with which air molecules push on a surface.

The atmosphere pushes down on the earth at

a pressure of 15 lb per in2.

As altitude increases, air pressure decreases.

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The layers of the atmosphere are:1) Troposphere

2) Stratosphere

3) Mesosphere

4) Thermosphere

5) Exosphere

7. The lowest layer of the atmosphere, which

lies next to the Earth’s surface, is called the

troposphere.

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8. Almost all the Earth’s carbon dioxide, water

vapor, clouds, air pollution, weather, and life-

forms are in the troposphere.

The atmospheric layer above the troposphere

is called the stratosphere.

9. The stratosphere contains the ozone layer.

The ozone layer protects life on Earth by

absorbing harmful ultraviolet radiation.

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The mesosphere is the middle layer of the

atmosphere.

10. The mesosphere is the coldest layer.

The uppermost atmospheric layer is called the

thermosphere.

The atoms in the thermosphere absorb solar

radiation making it the hottest layer.

11. Electrically charged particles are called

ions.

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In a part of the thermosphere, there are many

ions forming a layer called the ionosphere.

12. In the polar region these ions radiate

energy as shimmering lights called auroras.

The ions in the ionosphere reflect AM radio

waves.

This causes the AM radio signals to bounce

back to earth, allowing you to listen to a radio

station very far away.

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2.2 The earth receives energy from the sun by

radiation.

1. Radiation is the transfer of energy as

electromagnetic waves.

About fifty percent of the energy that

reaches the earth from the sun is absorbed

by the earth’s surface.

2. Thermal conduction is the transfer of

thermal energy through a material.

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Thermal energy is always transferred from

warm to cold areas.

3. Convection is the transfer of thermal energy

by the circulation or movement of a liquid or

gas.

When the air is heated it becomes less dense

and rises.

When the air is cooled it becomes more

dense and sinks.

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4. The cycle of warm air rising and cool air

sinking causes a circular movement of air

called a convection current.

The greenhouse effect is the process by

which gases in the atmosphere, such as water

vapor and carbon dioxide, absorb thermal

energy and radiate it back to the earth.

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The balance between incoming energy and

outgoing energy is known as the radiation

balance.

5. The increase in the average global

temperatures is called global warming.

Greenhouse gases are gases that absorb

thermal energy in the atmosphere.

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Human activity such as

burning fossil fuels and

deforestation may be

increasing levels of

greenhouse gases in the

atmosphere like carbon

dioxide.

Scientists are still debating

the effects of global

warming.

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2.3 1. The movement of air caused by

differences in air pressure is called wind.

The greater the difference in air pressure,

the faster the wind moves.

Differences in air pressure are generally

caused by unequal heating of the earth.

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2. Air travels in many large, circular patterns

called convection cells.

Convection cells are separated by pressure

belts, bands of high pressure and low

pressure found about every 30º of latitude.

The winds are not able to travel in a straight

line because the earth is rotating.

3. The apparent curving of the path of winds

and ocean currents due to the earth’s rotation

is called the Coriolis effect.

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The combination of convection cells found at every

30º of latitude and the Coriolis effect produces

patterns of air circulation called global winds.

4. The three major global wind systems:

1) Polar easterlies

2) Westerlies

3) Trade winds

The wind belts that extend from the poles to

60º latitude in both hemispheres are called the

polar easterlies.

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5. The wind belts found between 30º and 60º

latitude in both hemispheres are called the

westerlies.

6. In both hemispheres, the winds that blow

from 30º latitude almost to the equator are

called trade winds.

The westerlies carry moist air over the United

States producing rain and snow.

Early traders used the trade winds to sail from

Europe to the Americas.

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Global Winds

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7. The trade winds of the Northern and

Southern Hemispheres meet in an area

around the equator called the doldrums.

At about 30º north and 30º south latitude,

sinking air creates an area of high pressure

with weak winds called the horse latitudes.

Most of the world’s deserts are located in the

horse latitudes because the sinking air is very

dry.

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8. The jet streams are narrow belts of high-

speed winds that blow in the upper

troposphere and lower stratosphere.

The jet stream winds reach speeds of 400

km/hr or 250 mph.

The jet stream travels west to east across the

United States but not in a set pattern like the

global winds.

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Jet Stream

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Pilots study the jet stream to make trips

across the United States quicker.

9. Meteorologists study the jet stream to

predict the path of storms.

Near the ocean, the land heats up and cools

down quicker than the water creating local

winds.

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2.4 1. Air pollution is the contamination of the

atmosphere by the introduction of pollutants

from human and natural sources.

The two classifications of air pollution:

1) Primary pollutants

2) Secondary pollutants

Pollutants that are put directly into the air by

human or natural activity are primary

pollutants.

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Examples of natural primary pollutants:

Dust

Volcanic gases and ash

Smoke from forest fires

Pollen

Examples of human primary pollutants:

Vehicle exhaust

Smoke

Chemicals

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Pollutants that form when primary pollutants

react with other primary pollutants or with

naturally occurring substances are secondary

pollutants.

Smog is an example of secondary pollutants.

2. The two classifications of pollutants:

• Point-source pollutants

• Non-point source pollutants

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3. Point-source pollutants are pollutants that

are released from a single source.

Examples of point-source pollutants:

Smoke from burning brush

Chemical wastes

4. Non-point source pollutants are pollutants

that come from many different sources and

are often difficult to identify.

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Examples of non-point source pollutants:

Smog

Haze

Cars contribute about 10% to 20% of the

human-caused air pollution in the United

States.

Many industries burn fossil fuels and release

large amounts of air pollutants.

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Many houses also contain air pollution.

Causes of indoor air pollution:

Car or lawn mower exhaust

Household cleaners

Kerosene heaters

Wood stoves

5. Ventilation is the mixing of indoor air and

outdoor air.

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6. Precipitation such as rain, sleet, or snow

that contains acids from air pollution is called

acid precipitation.

Acid precipitation has damaged large areas of

forests.

Forests in the northeastern United States and

in eastern Canada have also been affected by

acid precipitation.

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Aquatic life has adapted to live in a certain

range of acidity.

7. A rapid change in a body of water’s acidity

is called acid shock.

Acid shock can kill a large number of fish in a

lake or river.

The effects of acid precipitation are worst in

the spring when the acidic snow that built up

in the winter melts and acidic water flows into

the lakes and rivers.

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To reduce the effects of acid precipitation on

aquatic ecosystems, some communities add

powdered limestone to acidified lakes.

Acid precipitation can cause toxic metals to be

released from the soil to be taken in by plants

and animals.

If humans eat these animals or plants, the

toxic metals can cause health problems.

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2.5 There are short-term and long-term effects

from air pollution.

Some short-term effects:

Headaches

Coughing

Irritation to your eyes, nose, and throat

Some long-term effects:

Lung cancer

Heart disease

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1. The abbreviation EPA stands for

Environmental Protection Agency.

In 1970, congress passed the Clean Air Act

that gave the EPA the power to regulate the

amount of air pollutants that can be released

from cars and factories.

The EPA has primary and secondary

standards.

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Primary standards protect against the effects

of air pollution on human health.

Secondary standards protect against the

effects of air pollution on crops, vegetation,

and buildings.

2. The abbreviation AQI stands for Air Quality

Index.

The color ratings of the AQI is not unhealthy

are green and yellow.

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3. The color rating of the AQI for hazardous is

maroon.

4. A scrubber is a device that is used to

remove some pollutants before they are

released by smokestacks.

Devices such as catalytic converters remove

any pollutants from exhaust and help cars

reduce pollutants.

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Cleaner fuels and more-efficient engines have

helped reduce air pollution.

Hybrids, which are cars that use gas and

electricity, also reduce air pollution.

Ways to reduce air pollution:

Car pooling

Public transportation

Walking or biking to your destination

Keeping your car in good condition

Conserving electricity